US4669022A - Magnetic-tape scanning device with improved rating transformer mounting and method of manufacturing such a device - Google Patents

Magnetic-tape scanning device with improved rating transformer mounting and method of manufacturing such a device Download PDF

Info

Publication number
US4669022A
US4669022A US06/456,237 US45623783A US4669022A US 4669022 A US4669022 A US 4669022A US 45623783 A US45623783 A US 45623783A US 4669022 A US4669022 A US 4669022A
Authority
US
United States
Prior art keywords
glue
transformer
scanning means
layer
rotatable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/456,237
Other languages
English (en)
Inventor
Juliaan J. M. R. Van Rooij
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Assigned to U.S. PHILIPS CORPORATION A CORP. OF DE reassignment U.S. PHILIPS CORPORATION A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: VAN ROOIJ, JULIAAN J.M.R.
Application granted granted Critical
Publication of US4669022A publication Critical patent/US4669022A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head
    • G11B5/53—Disposition or mounting of heads on rotating support
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head

Definitions

  • the invention relates to a magnetic-tape scanning device comprising a rotatable scanning means which is rotatable about a spindle axis and carries at least one magnetic head, and a rotary transformer; and more particularly to such a device which comprises a rotatable transformer ring, which is concentric with the spindle axis and which is secured to the rotatable scanning means, and a stationary transformer ring, which is secured to the stationary scanning means opposite the rotatable transformer ring so that a narrow axial air gap is formed between these rings.
  • At least one of the two transformer rings is mounted via a plurality of cylindrical supports for the transformer ring, which supports have a cylindrical surface and first and second end faces, and quantities of glue fuming a first layer of glue between the first end face of each support and the transformer ring and a second layer of glue for securing the transformer ring to the relevant scanning means.
  • Such magnetic-tape scanning devices are employed in magnetic video-tape recorders, for example Philips type VR 2020.
  • the transformer rings provide the contactless signal transfer from and to the rotating magnetic heads through the air gap between the two transformer rings.
  • the stationary transformer ring is supported by three supports.
  • the axial spacing between the two transformer rings should be very small, of the order of magnitude of nominally 60 microns with a tolerance of approximately 30 microns to each side.
  • This small dimension of the air gap should be maintained within a temperature range from -25° C. to +75° C. and for a relative humidity of 95% at 55° C. Since the rotatable transformer ring is arranged on the rotatable scanning means, and the stationary transformer ring is on the stationary scanning means, the dimension of the air gap between the two transformer rings will depend on the accuracy of the respective mountings of the rings to the scanning means, and the length of the axial air gap between the rotatable and the stationary scanning means.
  • the first end faces of the three supports are glued to that side of the transformer ring which is remote from the air gap by means of the first layer of glue.
  • the transformer ring is placed in a lathe and the second end faces of the supports are machined accurately. These second end faces serve to co-operate with a machined portion of the scanning means.
  • the scanning means should also be machined accurately, in particular the axial distance between the air gap edge of the scanning means and this machined portion must be formed very accurately and with a very small tolerance of the order of magnitude of 10 microns.
  • drops of glue are applied to that side of the transformer ring where the supports are situated, at locations between the supports.
  • the thickness of the layer of glue between the transformer ring and the scanning means may still vary, in particular under the influence of atmospheric moisture, such that the layer of glue becomes permanently thicker, which results in an undesired reduction of the air gap between the transformer rings.
  • the invention is characterized in that the relevant scanning means is formed with through holes which receive the supports with radial clearance, and the second layer of glue is an annular layer situated in that clearance, substantially exlusively between the inner wall of the hole and the cylindrical surface of the support.
  • the second layer of glue is subjected only to shear as a result of axial forces exerted on the transformer ring.
  • the second layer of glue can exert only forces in the shear direction on the transformer ring.
  • variations in the thickness of the second layer of glue as a result of variations in temperature and relative humidity do not occur in the shear direction, so that in principle the axial position of the transformer ring is not influenced at all.
  • the axial position of the transformer ring relative to the edge of the scanning means can be adjusted by accurate auxiliary tools and does not depend on the length of the supports.
  • a preferred embodiment of the invention is characterized in that the axial clearance between the transformer ring and the scanning means, which are connected to each other by the gluing means, is sufficient to prevent any excess of the glue, the forming the first layers of glue between the ends of the supports and the transformer ring, from making contact with the scanning means.
  • the use of the invention ensures that only the planar first layers of glue can influence the axial position of the transformer ring relative to the scanning means.
  • Another embodiment of the invention makes it possible to obtain a very short cycle time during assembly and is characterized in that the supports are made of a radiation-transparent material and at least one of the layers of glue is of a type of glue which cures under the influence of radiation.
  • This embodiment is possible because the supports are arranged in through holes, so that the second ends of the supports can be exposed to radiation, for example ultraviolet light.
  • the invention also relates to a method of manufacturing a magnetic-tape scanning device of the type described above foregoing.
  • This method is characterized in that the annular transformer ring and the scanning means to which this ring is to be secured are arranged on an auxiliary tool in the desired accurate position relative to each other.
  • the tool supports the transformer ring and the scanning means on the respective sides which should face the air gap between the two transformer rings, and the air gap between the two scanning means, respectively, and the supports are inserted from the other side of the scanning means.
  • the accuracy of the final product is determined not so much by the accuracy of the components used as by the accuracy of the auxiliary tool.
  • the use of the invention allows much larger tolerances in the thicknesses of the transformer rings.
  • the requirements imposed on the accuracy of the diameter and the length of the supports are not stringent.
  • the influence of the thickness in the axial direction of the first layers of glue may be reduced by the use of a variant of the method in accordance with the invention.
  • This variant is characterized in that the axial thickness of the first layers of glue, after application of these layers, is reduced by urging the supports and the transformer ring towards each other while the first layers of glue are still deformable. If the final layer of glue is thinner, possible variations in thickness of said layer become smaller.
  • the dimension of the axial air gap between the two transformer rings may be reduced to substantially half that existing in the known magnetic-tape scanning device.
  • the deviations of the final product may become some 30% smaller.
  • the diameter of the transformer rings may be reduced while maintaining the inductive coupling between the two transformer rings. This not only reduces the price of the transformer rings but it also mitigates problems which may arise as a result of warping of the transformer rings.
  • the supports, when they are made of metal, may consist of simple blanks and they require no finishing operation. Satisfactory results have been obtained with acrylate glue, a so-called second-generation glue comprising two components.
  • the curing time is approximately six minutes, so that a comparatively short cycle time can be achieved.
  • FIG. 1 is a side view and partly sectional view of a magnetic-tape scanning device showing the position of the two transformer rings
  • FIG. 2 is a plan view of the stationary scanning means shown in FIG. 1 with the stationary transformer ring mounted in said means, and
  • FIG. 3 is a sectional view of the lower scanning means shown in FIG. 1, in the inverted position, together with a transformer ring placed on an auxiliary tool.
  • the magnetic-tape scanning device comprises a spindle 1 with a spindle axis 2.
  • a rotatable scanning means in the form of a cylindrical head drum 4 is mounted on the spindle 22 and carries the magnetic heads 3.
  • a stationary scanning means 5, generally referred to as the lower drum, has an external guide surface 6 which is coaxial with the spindle axis for guiding a loop of magnetic tape 7 past the magnetic heads 3. For simplicity only a small part of the magnetic tape 7 is indicated by a broken line in FIG. 1.
  • the magnetic tape In the axial direction the magnetic tape is guided by a guide edge 8 on the lower drum 5.
  • This guide edge hs a helical shape so that the magnetic tape 7 can be guided in a helical path around the assembly comprising the head drum 4 and the lower drum 5.
  • Such a method of guiding the magnetic tape and such a method of recording and reading the magnetic tape are customary in any magnetic video-tape recorded for domestic use and will not be described in more detail.
  • the lower drum has an edge 9 at a small distance from a similar edge 10 of the head drum, so that a small axial air gap a is formed between the rotatable head drum 4 and the stationary lower drum 5.
  • transformer means In the interior of the assembly comprising the head drum and the lower drum transformer means are arranged, which means comprise a rotatable transformer ring 11A, which is concentric with the spindle axis 2 and which is arranged on the rotatable head drum, and a stationary transformer ring 11B, which is secured to the stationary lower drum opposite said first mentioned transformer ring so that a narrow axial air gap b is formed.
  • These transformer rings are made of a sintered ceramic material and their facing sides are surface-ground.
  • Transformer windings 12A and 12B of an electrically conductive wire material are arranged in grooves in the flat sides of the respective transformer rings. Each of the two transformer rings is secured to the head drum and the lower drum respectively by gluing means.
  • the gluing means comprise a plurality of cylindrical supports 13A and 13B, respectively, for the transformer rings 11A and 11B. They comprise cylindrical surfaces 14A and 14B, first end facess 15A and 15B and second end faces 16A and 16B. Furthermore, said means comprise an amount of glue for first layers of glue 17A and 17B between the first end faces of the supports and the transformer rings and second layers of glue 18A and 18B for securing the transformer rings to the head drum 4 and the lower drum 5.
  • the spindle 1 is journalled in the lower drum 5 by means of two sleeve bearings 19, of which the upper bearing is visible in FIG. 1.
  • the electric motor for driving the head drum 4 is accommodated in the lower part of the lower drum 5 and is irrelevant to the present invention. Of the electric motor an end shield 20 and a number of strips 21 for the electrical connection are visible.
  • Both the head drum and the lower drum are formed with through-going holes 22A and 22B which receive the supports with clearance.
  • said clearances 22A and 22B the second layers of glue 18A and 18B are situated almost exclusively between the inner walls of the holes and the cylindrical surfaces of the supports.
  • the dimension of the air gap b between the two transformer rings 11A and 11B depends only on the dimension of the air gap a between the head drum 4 and the lower drum 5 and on the thickness of the first layers of glue 17A and 17B.
  • Variations in the dimension of the air gap a as a result of temperature variations and variations in thickness of the layers of glue 17A and 17B as a result of temperature variations and/or variations of the relative humidity affect the dimension of the air gap b between the transformer rings.
  • the thicknesses of the second layers of glue 18A and 18B and variations in the thicknesses of these layers of glue have no effect.
  • gaps 23A and 23B formed of such axial dimensions as to preclude that glue of the first layers of glue 17A and 17B which has been urged away from between the first ends of the supports and the transformer rings comes into contact with the head drum 4 and with the lower drum 5, respectively.
  • the supports 13A and 13B may be made of a radiation-transparent material, for example glass or a plastics. Glass is preferred because of the small coefficient of thermal expansion and because glass does not absorb moisture from the air.
  • the first and second layers of glue may be a type of glue which cures under the influence of radiation, for example an ultraviolet-curing glue. Such types of glue are known and are used for example for connecting optical components to each other. The radiation can reach the layers of glue via the transparent support from the second ends 16A and 16B.
  • FIGS. 1 and 2 The method of manufacturing the magnetic-tape scanning device shown in FIGS. 1 and 2 will be described only in so far as the method relates to the fixation of the transformer ring 11B to the lower drum 5.
  • the transformer ring 11B and the lower drum 5 to which said ring is to be secured are placed on an auxiliary tool 24 in the desired accurate position relative to each other.
  • This auxiliary tool is formed with two accurately machined supporting surfaces 25 and 26 whose distance relative to each other is specified within very tight tolerances.
  • the transformer ring 11B is supported by the supporting surface 25 and the lower drum 5 is supported by the supporting surface 26 at those sides which should face the air gap b between the two transformer rings and the air gap a between the head drum and the lower drum, respectively.
  • the supports 13B are fitted from the top from that side of the lower drum 5 which faces the edge 9. After the desired amounts of glue have been applied the supports are inserted into the throughgoing holes 22B. After application the axial thickness of the first layers of glue 17B is reduced by loading the supports by a weight, not shown, during the time that the first layers of glue have not yet cured and are consequently deformable. By thus urging the supports and the transformer ring towards each other excess glue is squeezed sideways into the gap 23B between the transformer ring and the lower drum. Said gap, as already stated, is dimensioned so that no contact is possible between the excess glue and the lower drum.

Landscapes

  • Recording Or Reproducing By Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Facsimile Scanning Arrangements (AREA)
US06/456,237 1982-10-11 1983-01-07 Magnetic-tape scanning device with improved rating transformer mounting and method of manufacturing such a device Expired - Fee Related US4669022A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8203922 1982-10-11
NL8203922A NL8203922A (nl) 1982-10-11 1982-10-11 Magneetbandaftastinrichting en werkwijze voor het vervaardigen daarvan.

Publications (1)

Publication Number Publication Date
US4669022A true US4669022A (en) 1987-05-26

Family

ID=19840392

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/456,237 Expired - Fee Related US4669022A (en) 1982-10-11 1983-01-07 Magnetic-tape scanning device with improved rating transformer mounting and method of manufacturing such a device

Country Status (8)

Country Link
US (1) US4669022A (enrdf_load_stackoverflow)
EP (1) EP0107235B1 (enrdf_load_stackoverflow)
JP (1) JPS5994205A (enrdf_load_stackoverflow)
KR (1) KR910007865B1 (enrdf_load_stackoverflow)
DE (1) DE3369021D1 (enrdf_load_stackoverflow)
ES (1) ES283347Y (enrdf_load_stackoverflow)
HK (1) HK58788A (enrdf_load_stackoverflow)
NL (1) NL8203922A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4835645A (en) * 1986-11-05 1989-05-30 Hitachi, Ltd. Rotary magnetic head assembly
US4839762A (en) * 1986-06-25 1989-06-13 Canon Kabushiki Kaisha Rotary head device
US5515220A (en) * 1993-12-30 1996-05-07 Alioth; Henry L. Multielement disk-shaped rotary magnetic media scanners for magnetic media player-recorders
US20010013126A1 (en) * 1995-04-06 2001-08-09 United Video Properties, Inc. Interactive program guide systems and processes
US20140036464A1 (en) * 2012-08-02 2014-02-06 Infineon Technologies Ag Integrated System and Method of Making the Integrated System

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59157207U (ja) * 1983-04-06 1984-10-22 日本ビクター株式会社 テ−プガイドドラム
JPS6093602A (ja) * 1983-10-27 1985-05-25 Mitsubishi Electric Corp 回転機器アセンブリ
JPH0437282Y2 (enrdf_load_stackoverflow) * 1984-09-27 1992-09-02
GB2272988B (en) * 1992-10-30 1996-08-07 Samsung Electro Mech Drum of a tape recorder and an assembling method therefor
KR100232854B1 (ko) * 1997-10-23 1999-12-01 윤종용 자기 기록/재생 장치의 헤드 드럼

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974017A (en) * 1973-07-12 1976-08-10 Matsushita Electric Industrial Co., Ltd. Method of assembling a flat plate type rotary transformer
US4117519A (en) * 1976-10-27 1978-09-26 Matsushita Electric Industrial Co., Ltd. Guide drum apparatus in a magnetic recording and/or reproducing apparatus
US4210945A (en) * 1977-11-09 1980-07-01 Koshelev Alexandr G Rotary magnetic head assembly
US4408239A (en) * 1980-06-12 1983-10-04 Canon Kabushiki Kaisha Rotary magnetic head drum assembly for magnetically recording and/or reproducing device
US4517615A (en) * 1981-05-28 1985-05-14 Fuji Photo Film Co., Ltd. Rotary head for magnetic tape record and playback

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL136887C (enrdf_load_stackoverflow) * 1964-04-02
US3638934A (en) * 1967-11-06 1972-02-01 Bell & Howell Co Precision positioning tool
US3516146A (en) * 1968-06-19 1970-06-23 Westel Co Method of assembling a helical scanning assembly
DE1952369B2 (de) * 1969-10-17 1971-10-21 Blaupunkt-Werke Gmbh, 3200 Hildesheim Anordnung zur justierung von videokoepfen auf einem kopftraeger
US3679838A (en) * 1970-02-19 1972-07-25 Marlene D Graves Video tape scanner with adjustably mounted transducers providing chordal adjustment
US3867725A (en) * 1973-10-01 1975-02-18 Ibm Rotating head apparatus including a thrust gas bearing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974017A (en) * 1973-07-12 1976-08-10 Matsushita Electric Industrial Co., Ltd. Method of assembling a flat plate type rotary transformer
US4117519A (en) * 1976-10-27 1978-09-26 Matsushita Electric Industrial Co., Ltd. Guide drum apparatus in a magnetic recording and/or reproducing apparatus
US4210945A (en) * 1977-11-09 1980-07-01 Koshelev Alexandr G Rotary magnetic head assembly
US4408239A (en) * 1980-06-12 1983-10-04 Canon Kabushiki Kaisha Rotary magnetic head drum assembly for magnetically recording and/or reproducing device
US4517615A (en) * 1981-05-28 1985-05-14 Fuji Photo Film Co., Ltd. Rotary head for magnetic tape record and playback

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4839762A (en) * 1986-06-25 1989-06-13 Canon Kabushiki Kaisha Rotary head device
US4835645A (en) * 1986-11-05 1989-05-30 Hitachi, Ltd. Rotary magnetic head assembly
US5515220A (en) * 1993-12-30 1996-05-07 Alioth; Henry L. Multielement disk-shaped rotary magnetic media scanners for magnetic media player-recorders
US20010013126A1 (en) * 1995-04-06 2001-08-09 United Video Properties, Inc. Interactive program guide systems and processes
US20140036464A1 (en) * 2012-08-02 2014-02-06 Infineon Technologies Ag Integrated System and Method of Making the Integrated System
US9136213B2 (en) * 2012-08-02 2015-09-15 Infineon Technologies Ag Integrated system and method of making the integrated system
US9704843B2 (en) 2012-08-02 2017-07-11 Infineon Technologies Ag Integrated system and method of making the integrated system
US10224317B2 (en) 2012-08-02 2019-03-05 Infineon Technologies Ag Integrated system and method of making the integrated system

Also Published As

Publication number Publication date
EP0107235B1 (en) 1987-01-07
ES283347U (es) 1985-05-01
DE3369021D1 (en) 1987-02-12
NL8203922A (nl) 1984-05-01
JPH0159641B2 (enrdf_load_stackoverflow) 1989-12-19
JPS5994205A (ja) 1984-05-30
EP0107235A1 (en) 1984-05-02
KR910007865B1 (ko) 1991-10-02
HK58788A (en) 1988-08-12
ES283347Y (es) 1985-12-16
KR840006865A (ko) 1984-12-03

Similar Documents

Publication Publication Date Title
US4669022A (en) Magnetic-tape scanning device with improved rating transformer mounting and method of manufacturing such a device
US5311378A (en) Dual very-high density magnetic head assembly with optical servo positioning for very high density floppy disk recording and high density format compatability
US5675452A (en) Thin data storage device having a flexible recordable disk and recording heads arranged on both sides of the disk
EP0515786A1 (en) Thin film tape head assembly
US2864892A (en) Transducer mounting
US5063548A (en) Information processing apparatus
KR860001072B1 (ko) 회전형 자기 헤드장치
US4829657A (en) In-spindle motor assembly for disk drive and method for fabricating the same
US6299358B1 (en) UV-transparent elements for hard disk drive components
JPH06200927A (ja) ダイナミック溝ベアリングの製造方法及びそのような方法に用いる金型
US4692822A (en) Magnetic tape scanning unit and method of assembly thereof
US5357390A (en) Magnetic tape with a cylindrical magnetic head housing
US5731930A (en) Insulated wire guides for an actuator assembly
US4321639A (en) Apparatus for magnetically recording and reading wide-band signals
KR880003721Y1 (ko) 회전 자기 헤드 드럼
US6661616B2 (en) Head drum assembly and tape drive using the same
CA1070423A (en) Helical scan magnetic recording device having a folded mounting plate
US4424539A (en) Magnetic disk-control track read through envelope
JP2652990B2 (ja) スピンドルモータ
JPH04283403A (ja) 磁気記録再生装置の回転ドラム装置
KR100228691B1 (ko) 회전 헤드 드럼 장치
MY101119A (en) Tape reel assemblies for magnetic tape cassettes.
JPS5927969B2 (ja) 遠心力型磁気ヘツドの製造方法
JP3078740B2 (ja) 回転ドラム装置
KR200156670Y1 (ko) 테이프 레코더의 헤드 드럼

Legal Events

Date Code Title Description
AS Assignment

Owner name: U.S. PHILIPS CORPORATION 100 EAST 42ND ST., NEW YO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:VAN ROOIJ, JULIAAN J.M.R.;REEL/FRAME:004092/0005

Effective date: 19830118

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19950531

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362